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TinyMito

macrumors 6502a
Original poster
Nov 1, 2021
865
1,227
I like to ask and discuss where on the MacBook Pro M1 series are limited to HDMI 2.0. I am quite puzzled by the fact that this is not an M1 CPU/GPU bandwidth limitation?

My MacBook Pro M1 Pro is capable of running 4K at 120Hz/144Hz(DSC) with the following setup:
- USB-C to USB-C Monitor Alt-DP mode to monitor.
- USB-C to DisplayPort 1.4 adapter to monitor.
- This also works over my CalDigit Element Hub

What doesn't work, anything to HDMI output:
- USB-C to HDMI 2.1 adapter with HDMI 2.1 cable to monitor stuck at 4K 60Hz only.
- HDMI 2.0 port from the MacBook Pro itself, 4k 60Hz.

Where exactly is this limited? Even with an HDMI 2.1 adapter, it would still be stuck at 2.0. Except, DisplayPort/Alt-DP can go full range that proof that the M1 chip can support high resolution and refresh rate, just not via the HDMI.

I wonder if this is by designed due to certification of HDMI 2.1 was not approved?

Some source proof M1 Pro can support:
 
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